._setArrow(@arrowsize, @borderColor, @borderWidth) {
  display: inline-block;
  height: @arrowsize;
  width: @arrowsize;
  border-width: @borderWidth @borderWidth 0 0;
  border-color: @borderColor;
  border-style: solid;
}

.setArrow(@direction, @arrowsize, @borderColor, @borderWidth) when (@direction =top) {
  ._setArrow(@arrowsize, @borderColor, @borderWidth);
  transform: matrix(0.71, -0.71, 0.71, 0.71, 0, 0); // rotate(-45deg)
}

.setArrow(@direction, @arrowsize, @borderColor, @borderWidth) when (@direction =right) {
  ._setArrow(@arrowsize, @borderColor, @borderWidth);
  transform: matrix(0.71, 0.71, -0.71, 0.71, 0, 0); // rotate(45deg);
  position: relative;
  top: -.04rem;
}

.setArrow(@direction, @arrowsize, @borderColor, @borderWidth) when (@direction =down) {
  ._setArrow(@arrowsize, @borderColor, @borderWidth);
  transform: matrix(-0.71, 0.71, -0.71, -0.71, 0, 0); // rotate(135deg);
  position: relative;
  top: -.06rem;
}

.setArrow(@direction, @arrowsize, @borderColor, @borderWidth) when (@direction =left) {
  ._setArrow(@arrowsize, @borderColor, @borderWidth);
  transform: matrix(-0.71, -0.71, 0.71, -0.71, 0, 0); // rotate(-135deg);
  position: relative;
  top: -.04rem;
}
